The present invention relates to a granulator which comprises a granulator mill housing with a fixed section and an opening hatch which is pivotally connected to the fixed section by the intermediary of a first pivot with a substantially vertical first pivot axis, the granulator mill housing having a number of fixed knives, a rotor rotatably disposed in the granulator mill housing, with a number of knives, and a discharge section for discharging granulate material.
In the employment of granulators in the plastics industry for recovery or recycling of plastics materials, it is necessary to carefully clean the interior of the granulator before changing from one plastics quality or colour to another. This implies requirements that the interior of the granulator be readily accessible for cleaning. This also applies to the discharge section of the granulator in which the granulate material is accumulated and from which it is discharged, often via conduits or chutes. For this reason, it is previously known in the art to design a granulator in such a manner that its granulator mill housing has an opening section or a hatch, by the intermediary of which the interior of the granulator mill housing and the rotor disposed therein are rendered accessible.
There is also a trend in the plastics industry that granulators are produced in increasingly larger sizes. This implies that the opening section or hatch of the granulator mill housing will be of considerable weight, which requires machine power for opening and closing if the pivot axis of the hatch is horizontal.
WO 03/033156 discloses a granulator of the above-outlined, prior art type. According to this publication, the problem inherent in a large and heavy opening section of the granulator mill housing is solved in that this section is pivotally disposed about a vertical axis. According to this publication, the opening section is pivotal within a large angle sector, so that extremely good accessibility to the interior of the granulator mill housing, the rotor and also the discharge section of the granulator is achieved.
Surrounding granulators in an industrial environment, there is often a considerable quantity of peripheral equipment, for which reason space is often at a premium. In a large granulator of the type which is illustrated in WO 03/033156, the opening section of the granulator mill housing may have a length in excess of 1 m. This implies that the sweep surface in which the opening section moves on opening and closing, often of the order of magnitude of 180°, is considerable and naturally must be kept completely free of peripheral equipment.
It is desirable to design the granulator described by way of introduction such that the drawbacks inherent in the prior art technology are obviated. In particular, it is desirable to design the granulator so that its interior may be accessed in an extremely simple manner for cleaning, with attendant superior accessibility both to the interior of the granulator mill housing, the rotor disposed therein and the discharge section of the granulator, without the need for a large space free of peripheral equipment in order to permit opening of the opening section or hatch of the granulator.
According to an aspect of the present invention, a granulator intimated by way of introduction is characterised in that the opening hatch comprises a first and a second part which are pivotally connected to one another via a second pivot with a substantially vertical pivot axis.